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Abstract:

A heat dissipation device for a first electronic component and a second
electronic component mounted on a circuit board includes a first base
mounted on the first electronic component and a second base mounted on
the second electronic component. The second base is movably connected
with the first base. An electronic system incorporating the heat
dissipation device is also provided.

Claims:

1. A heat dissipation device for a first electronic component and a
second electronic component mounted on a circuit board, the heat
dissipation device comprising: a first base configured to be mounted on
the first electronic component; and a second base configured to be
mounted on the second electronic component, the second base moveably
connected with the first base.

2. The heat dissipation device of claim 1, wherein the first base is
pivotally connected with the second base.

3. The heat dissipation device of claim 1, wherein the first base
comprises an orienting portion extending toward the second base, the
second base comprises a connecting portion extending toward the first
base, and the connecting portion is moveably connected with the orienting
portion.

4. The heat dissipation device of claim 3, wherein the second base
comprises a heat spreader and a fastening assembly configured for
mounting the heat spreader on the second electronic component, and the
connecting portion extends from one of the spreader and the fastening
assembly.

5. The heat dissipation device of claim 3, wherein the orienting portion
comprises an annular flange defining an orienting hole therein, the
connecting portion defines a connecting hole therein, the flange extends
through the connecting hole, and a fastener is received in the orienting
hole thereby pivotally connecting the second base with the first base.

6. The heat dissipation device of claim 5, wherein the fastener comprises
a head at a top end thereof, a thickness of the connecting portion is
less than a height of the flange, a diameter of the connecting hole is
greater than an outer diameter of the flange but less than an outer
diameter of the head of the fastener, and the connecting portion is
located between the orienting portion and the head of the fastener.

7. The heat dissipation device of claim 6, further comprising a fin
assembly, a first heat pipe thermally connecting the first base with the
fin assembly, and a second heat pipe thermally connecting the second base
with the fin assembly.

8. The heat dissipation device of claim 7, further comprising a fan
mounted on the first base, the fin assembly configured to be disposed at
an air outlet of the fan, the fin assembly comprising a plurality of
stacked fins, each of the fins bent toward a lateral side thereof at one
end away from the fan.

9. The heat dissipation device of claim 7, wherein the first base
comprises a bracket away from the second base, the fin assembly is
disposed on the bracket, and the first and second heat pipes each
comprise a condensation section received in the fin assembly.

10. The heat dissipation device of claim 9, wherein the bracket comprises
two extension arms extending from the first base and a support plate
connecting the extension arms, and a pair of tabs extend up from opposite
ends of the support plate and abut against two outermost fins of the fin
assembly, respectively.

11. The heat dissipation device of claim 10, wherein the first base
further comprises a mounting rack and a bottom plate at a bottom of the
mounting rack, the bottom plate is configured to be attached to the first
electronic component, the mounting rack comprises a top plate and four
fixing legs extending outwardly from four corners of the top plate,
respectively, the top plate arches at a middle thereof, an evaporation
section of the first heat pipe is received between the top and bottom
plates, each of the fixing legs forms a mounting sleeve at a distal end
thereof, and the extension arms of the bracket extend respectively from
outer circumferential surfaces of two adjacent mounting sleeves of the
fixing legs.

12. An electronic system, comprising: a circuit board comprising a first
electronic component and a second electronic component; a first base
mounted on the first electronic component; and a second base mounted on
the second electronic component, the second base moveably connected with
the first base.

13. The electronic system of claim 12, wherein the first base comprises
an orienting portion extending toward the second base, the second base
comprises a connecting portion extending toward the first base, and the
connecting portion is moveably connected with the orienting portion.

14. The electronic system of claim 13, wherein the second base comprises
a heat spreader and a fastening assembly configured for mounting the heat
spreader on the second electronic component, and the connecting portion
extends from one of the spreader and the fastening assembly.

15. The electronic system of claim 13, wherein the orienting portion
comprises an annular flange defining an orienting hole therein, the
connecting portion defines a connecting hole therein, the flange extends
through the connecting hole, and a fastener is received in the orienting
hole thereby pivotally connecting the second base with the first base.

16. The electronic system of claim 15, wherein the fastener comprises a
head at a top end thereof, a thickness of the connecting portion is less
than a height of the flange, a diameter of the connecting hole is greater
than an outer diameter of the flange, but less than an outer diameter of
the head of the fastener, and the connecting portion is located between
the orienting portion and the head of the fastener.

17. The electronic system of claim 16, further comprising a fin assembly,
a first heat pipe thermally connecting the first base with the fin
assembly, and a second heat pipe thermally connecting the second base
with the fin assembly.

18. The electronic system of claim 17, wherein the first base comprises a
bracket away from the second base, the fin assembly is disposed on the
bracket, and the first and second heat pipes each comprise a condensation
section received in the fin assembly.

19. The electronic system of claim 18, wherein the bracket comprises two
extension arms extending from the first base and a support plate
connecting the extension arms, and a pair of tabs extend upward from
opposite ends of the support plate and abut against two outermost fins,
respectively.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application is related to a co-pending application entitled
"ELECTRONIC SYSTEM AND HEAT DISSIPATION DEVICE THEREOF" (attorney docket
number US31488), assigned to the same assignee of this application and
filed on the same date as this application.

BACKGROUND

[0002] 1. Technical Field

[0003] The disclosure generally relates to heat dissipation, and
particularly to a heat dissipation device for plural electronic
components of an electronic system.

[0004] 2. Description of Related Art

[0005] It is well known that heat is generated by electronic components
such as integrated circuit chips, during their operation. If the heat is
not efficiently removed, the electronic components may suffer damage.
Thus, heat dissipation devices are often used to cool the electronic
components.

[0006] In a typical computer system, more than one electronic component,
such as a central processing unit (CPU), a memory control hub (MCH), an
input/output (i/o) controller hub (ICH), and others, must be cooled.
Since the electronic components are generally of different heights with
top surfaces thereof at different levels, a lone conventional heat sink
cannot make the required snug contact with the top surfaces of all the
components. Accordingly, a plurality of heat pipes is often employed to
remove heat from the electronic components. However, if the heat pipes
are fully fixed, there is no moveable space to meet product tolerances.
This results in contact gaps between the heat pipes and the electronic
components. Thus, the heat dissipation efficiency of the heat dissipation
device may be adversely affected. Further, if the heat pipes are not
fixed, they may deform during transport or assembly.

[0007] What is needed, therefore, is a heat dissipation device and an
electronic system incorporating the heat dissipation device which can
overcome the described limitations.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Many aspects of the present embodiments can be better understood
with reference to the following drawings. The components in the drawings
are not necessarily drawn to scale, the emphasis instead placed upon
clearly illustrating the principles of the present embodiments. Moreover,
in the drawings, like reference numerals designate corresponding parts
throughout the various views.

[0009] FIG. 1 is an assembled, isometric view of an electronic system in
accordance with one embodiment of the disclosure.

[0010] FIG. 2 is an exploded view of the electronic system of FIG. 1.

[0011] FIG. 3 is an enlarged view of a circled portion III of the
electronic system shown in FIG. 2.

[0012] FIG. 4 is an enlarged, exploded view of a fastening assembly of the
electronic system of FIG. 1.

[0013] FIG. 5 is an isometric view of a fan disassembled from the
electronic system of FIG. 1.

[0014] FIG. 6 is an inverted view of a heat spreader disassembled from a
heat dissipation device of the electronic system of FIG. 1.

DETAILED DESCRIPTION

[0015] Referring to FIGS. 1 and 2, an electronic system in accordance with
one embodiment of the disclosure is shown. The electronic system includes
a circuit board 70, and a heat dissipation device mounted on the circuit
board 70. The circuit board 70 supports a first electronic component 72
such as a CPU, and a second electronic component 74 such as an MCH, ICH,
or other component. In the illustrative embodiment, the first electronic
component 72 generates more heat than the second electronic component 74
during operation. The circuit board 70 defines therein a mounting hole 76
near each corner of the first electronic component 72, and provides a
pair of clasps 78 near two diagonally opposite corners of the second
electronic component 74. The heat dissipation device includes a first
base 10 mounted on the first electronic component 72, a fan 20 located on
the first base 10, a fin assembly 30 disposed beside the fan 20, a second
base mounted on the second electronic component 74, and a heat pipe
assembly 50 thermally connecting the first base 10 and the second base
with the fin assembly 30. The second base includes a heat spreader 40,
and a fastening assembly 60 fixing the heat spreader 40 onto the second
electronic component 74.

[0016] The first base 10 includes a mounting rack 12, and a rectangular
bottom plate 14 at a bottom of the mounting rack 12. The bottom plate 14
is made of metal or metal alloy with a high heat conductivity
coefficient, such as copper, copper-alloy, or other suitable material.
The bottom plate 14 is attached to the first electronic component 72 of
the circuit board 70. The bottom plate 14 defines a plurality of parallel
and spaced receiving grooves 140 in a top surface thereof, for receiving
the heat pipe assembly 50. The mounting rack 12 includes a rectangular
top plate 122 and four fixing legs 124 extending outwardly from four
corners of the top plate 122, respectively. The top plate 122 defines a
plurality of parallel and spaced receiving grooves 1220 in a bottom
surface thereof, corresponding to the receiving grooves 140 of the bottom
plate 14. The top plate 122 arches at a middle thereof, corresponding to
the receiving grooves 1220. Two lateral sides of the top plate 122 are
thinner than the arched portion of the top plate 122, for saving material
and reducing the weight of the first base 10. Each of the fixing legs 124
forms a mounting sleeve 1240 at a distal end thereof. Four fasteners 100
extend respectively through the mounting sleeves 1240 of the fixing legs
124, for mounting the heat dissipation device on the circuit board 70.
Three of the fixing legs 124 each include a fixing arm 126 extending
outwardly from a lateral side thereof. The fixing arm 126 is parallel to
the receiving grooves 1220, and defines an internally threaded sleeve
1260 at a distal end thereof.

[0017] The mounting rack 12 further includes a bracket 127 and an
orienting portion 128, which are at opposite sides of the top plate 122,
respectively. The bracket 127 is located away from the second electronic
component 74. The bracket 127 includes two extension arms 1272 extending
respectively from outer circumferential surfaces of two adjacent mounting
sleeves 1240 of the fixing legs 124, and a support plate 1274 connecting
two free ends of the extension arms 1272. A pair of tabs 1270 extend
perpendicularly upward from opposite ends of the support plate 1274,
respectively. The orienting portion 128 extends from the top plate 122
toward the second electronic component 74, and is perpendicular to the
receiving grooves 1220. Referring also to FIG. 3, in the present
embodiment, the orienting portion 128 is an elongated rectangular plate.
The orienting portion 128 includes an annular collar 1280 extending
perpendicularly upward from a distal end of a main body thereof. The
collar 1280 defines an orienting hole 1282 therein.

[0018] The fan 20 is a centrifugal blower, and directs airflow toward the
fin assembly 30. The fan 20 includes a substantially rectangular housing
22. The housing 22 includes three ears 24 extending out from a bottom end
thereof, corresponding to the fixing arms 126, respectively. Each of the
ears 24 defines a fixing hole 240 therethrough. A fastener 200 extends
through the fixing hole 240 of each ear 24 and is received in the
internally threaded sleeve 1260, the fasteners 200 thereby securing the
fan 20 to the mounting rack 12 of the first base 10.

[0019] The fin assembly 30 is disposed on the support plate 1274 of the
bracket 127, adjacent to an air outlet (not shown) of the fan 20. The fin
assembly 30 includes a plurality of stacked fins 32. An air channel 36
(shown in FIG. 6) is defined between every two adjacent fins 32. Each of
the fins 32 is bent toward a lateral side thereof at one end away from
the fan 20, with the air channel 36 between every two adjacent fins 32
forming a corresponding shape, thereby deflecting the airflow from its
original direction to generate turbulent airflow. This reduces airflow
retention on outer surfaces of the fins 32, and enhances heat transfer
efficiency between the airflow and the fins 32. The fin assembly 30
defines a plurality of parallel and spaced accommodating holes 34
therein. The accommodating holes 34 extend through the fins 32. The tabs
1270 of the bracket 127 abut against two outermost fins 32, respectively,
preventing lateral sliding of the fin assembly 30.

[0020] The heat pipe assembly 50 includes a plurality of first heat pipes
52 thermally connecting the first base 10 with the fin assembly 30, and a
second heat pipe 54 thermally connecting the heat spreader 40 with the
fin assembly 30. The first heat pipes 52 are generally U-shaped, and each
includes an evaporation section 522, a condensation section 524, and an
adiabatic section 526 interconnecting the evaporation section 522 and the
condensation section 524. The second heat pipe 54 is flattened, and
includes an evaporation section 542, a condensation section 544, and an
adiabatic section 546 interconnecting the evaporation section 542 and the
condensation section 544. The adiabatic section 546 of the second heat
pipe 54 is longer than the adiabatic section 526 of each first heat pipe
52. The condensation sections 524, 544 of the first and second heat pipes
52, 54 are received in the accommodating holes 34 of the fin assembly 30,
respectively. The evaporation sections 522 of the first heat pipes 52 are
received in cylindrical receiving holes cooperatively formed by the
receiving holes 140, 1220 of the top and bottom plates 14, 122 of the
first base 10, respectively. The evaporation section 542 of the second
heat pipe 54 is attached to a top surface of the heat spreader 40. The
adiabatic sections 526, 546 of the first and second heat pipes 52, 54 are
located beside the fan 20.

[0021] The heat spreader 40 is generally rectangular, and made of metal or
metal alloy which has a high heat conductivity coefficient, such as
copper, copper-alloy, or other suitable material. The heat spreader 40 is
attached to the second electronic component 74 of the circuit board 70.

[0022] Referring also to FIG. 4, the fastening assembly 60 includes a
retention rack 62 mounting the evaporation section 542 of the second heat
pipe 54 on the heat spreader 40, and a wire clip 64 securing the heat
spreader 40 on the second electronic component 74. The retention rack 62
includes a retention plate 620, and a connecting portion 629 extending
from the retention plate 620. The retention plate 620 is substantially
rectangular, and defines an elongated opening 622 and a slot 624 crossing
the opening 622. The opening 622 extends diagonally along the retention
plate 620, defining two substantially triangular portions of the
retention plate 620. The slot 624 extends along an axis perpendicular to
opposite lateral sides of the retention plate 620, and divides each
triangular portion of the retention plate 620 into two portions. The
opening 622 is wider than the evaporation section 542 of the second heat
pipe 54, and the slot 624 is wider the wire clip 64.

[0023] The retention plate 620 includes a pair of retaining portions 626
and a pair of fastening portions 628. The retaining portions 626 are
saddle-shaped. The retaining portions 626 span the opening 622, and
interconnect the triangular portions of the retention plate 620 divided
by the opening 622. The fastening portions 628 are substantially
semicylindrical. Considered another way, the fastening portions 628 are
in the form of arc-shaped bridges. The fastening portions 628 span the
slot 624, and interconnect the portions of the retention plate 620
divided by the slot 624. The retention plate 620 defines therein a
plurality of rivet holes 627 beside the retaining portions 626, the
fastening portions 628 and the connecting portion 629.

[0024] The connecting portion 629 is integrally formed with the retention
plate 620 as a single piece. That is, the retention plate 620 is a
single, one-piece monolithic body which includes the connecting portion
629. Alternatively, the connecting portion 629 can extend integrally from
the heat spreader 40, or be welded or riveted on the heat spreader 40.
The connecting portion 629 is moveably connected with the orienting
portion 128 of the mounting rack 12. Namely, the retention rack 62 with
the connecting portion 629 is moveable in a permitted range with respect
to the orienting portion 128. In this embodiment, the connecting portion
629 is laminar, and includes an oblique portion 6292 extending obliquely
upward from an edge of the retention plate 620, and a planar portion 6294
extending horizontally from a top end of the oblique portion 6292. A
thickness of the planar portion 6294 is less than a height of the collar
1280 of the orienting portion 128. The planar portion 6294 defines a
connecting hole 6290 in a distal end thereof. A diameter of the
connecting hole 6290 is greater than an outer diameter of the collar
1280. The collar 1280 extends through the connecting hole 6290. A
fastener 300 with a head 301 larger the connecting hole 6290 is received
in the orienting hole 1282, for pivotally connecting the retention rack
62 of the second base with the first base 10. The planar portion 6294 of
the connecting portion 329 is located between the orienting portion 128
and the head 301 of the fastener 300. Thus, the retention rack 62 is not
only moveable up and down, but is also rotatable horizontally with
respect to the collar 1280 of the first base 10.

[0025] The wire clip 64 is integrally made of a metal wire. The wire clip
64 includes a middle member 642, and two locking arms 644 extending
perpendicularly and outwardly from opposite ends of the middle member 642
toward generally opposite directions. Each of the locking arms 644 forms
a hook 6440 at a distal end thereof. The middle member 642 includes two
abutting portions 6422, and a resisting portion 6242 interconnecting the
abutting portions 6422. The resisting portion 6242 arches from two
adjacent ends of the abutting portions 6422. The two locking arms 644
extending outwardly from two outer ends of the abutting portions 6422
toward generally opposite directions, respectively. The wire clip 64 is
symmetrical with respect to the resisting portion 6242.

[0026] Referring also to FIGS. 5 and 6, the retention plate 620 of the
retention rack 62 is riveted on the heat spreader 40 via the rivet holes
627, with the evaporation section 542 of the second heat pipe 54 and the
abutting portions 6422 of the wire clip 64 respectively received in the
opening 622 and the slot 624 of the retention plate 620. The retaining
portions 626 of the retention plate 620 and the resisting portion 6242 of
the wire clip 64 abut against a top surface of the evaporation section
542 of the second heat pipe 54, and the abutting portions 6422 of the
wire clip 64 abut against inner surfaces of the fastening portions 628.
The locking arms 644 of the wire clip 64 are pressed downward until the
hooks 6440 of the locking arms 644 clasp the clasps 78 of the circuit
board 70.

[0027] In the present heat dissipation device, the retention rack 62 of
the second base is movably connected with the first base 10 via the
connecting portion 629. Therefore, the second heat pipe 54 thermally
connecting the second base with the fin assembly 30 does not deform
easily during transport and assembly. In addition, there is required
moveable space between the retention rack 62 of the second base and the
first base 10 to meet product tolerances, such that a contact gap between
the second heat pipe 54 and the heat spreader 40 is avoided. Thus, the
heat dissipation efficiency of the heat dissipation device is enhanced.

[0028] It is to be understood, however, that even though numerous
characteristics and advantages of the present embodiments have been set
forth in the foregoing description, together with details of the
structures and functions of the embodiments, the disclosure is
illustrative only, and changes may be made in detail, especially in
matters of shape, size, and arrangement of parts within the principles of
the invention to the full extent indicated by the broad general meaning
of the terms in which the appended claims are expressed.